JP3295598B2 - Internal combustion engine piston ring - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a piston ring for an internal combustion engine.

[0002]

2. Description of the Related Art A piston of an internal combustion engine has a clearance between the cylinder wall and the piston to absorb thermal expansion, and a piston ring 3 is mounted in a ring groove 2 on the outer periphery of the piston 1 as shown in FIG. The piston ring 3 is composed of a compression ring 3a for sealing the combustion pressure and an oil ring 3b for adjusting the lubricating oil film on the cylinder wall surface 4. The piston ring 3 performs these functions while sliding back and forth on the cylinder wall surface 4. It has become.

[0003]

By the way, the piston 1
With the reciprocation of the piston ring 3, the side clearance m
Move (side clearance) up and down. for that reason,
Since the ring groove 2 of the piston 1 is hit and wears out,
There was a problem that the combustion pressure leaked, the oil consumption deteriorated, and the number of blow-by tended to increase. Further, there is also a surface in which oil is scraped up by the vertical movement of the piston ring 3 and the consumption thereof is increased.

An object of the present invention is to provide an effective countermeasure for solving such a problem.

[0005]

According to a first aspect of the present invention, in a piston ring to be assembled to a piston of an internal combustion engine through a ring groove on an outer periphery thereof, a cross section of the ring is formed in a U-shape or a box shape. Spring means for pressing the upper and lower surfaces against the wall surface of the ring groove of the piston from the inside is added.

In the second invention, the pressing force of the spring means in the first invention is larger than the inertial force of the ring itself due to the reciprocating motion of the piston, and the frictional force of the ring in the radial direction is smaller than the ring tension. Set to stop.

[0007]

According to the first aspect of the present invention, there is no side clearance with the ring groove due to the pressing force of the spring means, and it is possible to prevent the leakage of combustion pressure, the increase of blow-by and the deterioration of oil consumption for a long time.
Further, since the cross-sectional shape of the ring is U-shaped or box-shaped, weight reduction of the piston ring can be promoted.

According to the second aspect, even if the pressing force of the spring means decreases due to the inertial force of the ring itself due to the reciprocating motion of the piston, there is no side clearance with the ring groove. Further, the frictional force in the radial direction based on the pressing force of the spring means is smaller than the ring tension, and the piston ring can maintain a good contact state with the cylinder wall surface.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIGS. 1 to 3, reference numeral 10 denotes a compression ring as a piston ring, which is assembled in a ring groove 12 on the outer periphery of a piston 11. The piston ring 10 is formed in a U-shaped cross section in this example, and a spring means 13 for pressing the upper and lower surfaces of the ring against the wall surface of the ring groove 12 from the inside thereof is provided. An annular wave-shaped spring is housed inside the ring 10 as the spring means 13 and urges the upper and lower surfaces with a predetermined pressing force F.

The pressing force F of the spring means 13 is
Greater than the inertia force of the ring 10 itself due to the reciprocating motion of the frictional force small stop General Domel so than the ring tension W in the radial direction, because these conditions are _{satisfied, F> ρ [W R /} g · R ・ (π ・ N / 30) ²・ (1 + R /
L)] and F <W _min / μ, where ρ; ring weight distribution ratio W _R ; ring weight g; gravitational acceleration R; radius of piston stroke N; rated engine rotation L; length of connecting rod W _min ; Tension μ: Set to the friction coefficient between piston and ring.

In order to increase the rigidity of the piston ring 10,
As shown in FIG. 3, a joint member 15 that joins the joint 14 is provided. The joint member 15 is only one of the rings 1
The other end is displaceably engaged with the ring 10 in order to secure the function of the abutment 14 for absorbing thermal expansion.

With such a configuration, the pressing force of the spring means 13 eliminates the side gap with the ring groove 12 and secures the surface pressure, so that it is possible to prevent leakage of combustion pressure, increase of blow-by, and deterioration of oil consumption. . By forming the cross-sectional shape of the ring 10 into a U-shape and performing the aforementioned abutment process, it is possible to promote the reduction in weight of the piston ring while securing the rigidity of the ring 10.

Ring 10 accompanying reciprocation of piston 11
Although the inertial force of the spring acts in a direction to decrease the pressing force F of the spring means 13, the pressing force F of the spring means 13 overcomes the inertial force, so that there is no temporary margin of the side clearance. Further, since the frictional force in the radial direction based on the pressing force F of the spring means 13 is smaller than the ring tension W, the piston ring 10 can maintain a good contact state with the cylinder wall surface.

The spring means 13 may be provided by the material of the ring 10. Further, if the thickness of the ring 10 is not uniform and the thickness t ₁ of the upper and lower surfaces and the thickness t ₂ of the sliding surface are set to t ₁ <t _{2 as shown} in FIG. Power can be reduced. The cross-sectional shape of the ring 10 is shown in FIG.
It may be formed in a box shape as shown in FIG. In that case, the back of the ring is not integral, but is separated at its center. Alternatively, both ends may be overlapped as shown in FIG.

[0015]

According to the first aspect of the present invention, in a piston ring to be assembled to a piston of an internal combustion engine through a ring groove on an outer periphery thereof, the cross section of the ring is formed into a U-shape or a box-shape, Since the spring means for pressing the upper and lower surfaces against the wall surface of the ring groove of the piston is added, there is no side gap with the ring groove, so that leakage of combustion pressure, increase of blow-by and deterioration of oil consumption can be prevented for a long time.
Further, weight reduction of the piston ring can be promoted.

According to the second invention, the pressing force of the spring means in the first invention is larger than the inertial force of the ring itself due to the reciprocating motion of the piston, and the frictional force in the radial direction of the ring is made smaller than the ring tension. Is set to be small, so that there is no possibility that a side gap is generated due to the inertial force of the ring itself due to the reciprocating motion of the piston. Further, the frictional force in the radial direction is smaller than the ring tension, and the piston ring can maintain a good contact state with the cylinder wall surface.

[Brief description of the drawings]

FIG. 1 is a partial sectional view showing an assembled state of a piston according to an embodiment of the present invention.

FIG. 2 is a partially exploded perspective view of the piston ring.

FIG. 3 is an explanatory diagram of a joint process.

FIG. 4 is a partial cross-sectional view illustrating modified examples (a) to (c) of a piston ring.

FIG. 5 is an explanatory diagram of a conventional technique.

[Explanation of symbols]

 Reference Signs List 10 piston ring 11 piston 12 ring groove 13 spring means

Claims (2)

(57) [Claims] 1. A piston ring which is assembled to a piston of an internal combustion engine via a ring groove on the outer periphery of the piston ring. A piston ring for an internal combustion engine, wherein spring means for pressing against a wall surface of the internal combustion engine is added. The pressing force of the spring means is set to be larger than the inertia force of the ring itself due to the reciprocating movement of the piston, and the frictional force in the radial direction of the ring is set to be smaller than the ring tension. The piston ring according to claim 1, wherein: